varnish_wordpress.vcl

# Supports admin cookies for wp-admin
# Caches everything
# Configure your webserver to run on port 88

vcl 4.0;
import directors;
import std;

# Assumed 'wordpress' host, this can be docker servicename
backend default {
    .host = "localhost";
    .port = "88";
}

acl purge {
    "localhost";
        "127.0.0.1";
}


sub vcl_recv {

        # Only a single backend
        set req.backend_hint= default;

        # Setting http headers for backend
        set req.http.X-Forwarded-For = client.ip;

        # Unset headers that might cause us to cache duplicate infos
        unset req.http.Accept-Language;
        unset req.http.User-Agent;

        # The purge...no idea if this works
                if (req.method == "PURGE") {
                    if (!client.ip ~ purge) {
                      return(synth(405,"Not allowed."));
                    }
                    return (purge);
                }
        # drop cookies and params from static assets
        if (req.url ~ "\.(gif|jpg|jpeg|swf|ttf|css|js|flv|mp3|mp4|pdf|ico|png)(\?.*|)$") {
                unset req.http.cookie;
                set req.url = regsub(req.url, "\?.*$", "");
        }

        # drop tracking params
        if (req.url ~ "\?(utm_(campaign|medium|source|term)|adParams|client|cx|eid|fbid|feed|ref(id|src)?|v(er|iew))=") {
                set req.url = regsub(req.url, "\?.*$", "");
        }

        # pass wp-admin urls
        if (req.url ~ "(wp-login|wp-admin)" || req.url ~ "preview=true" || req.url ~ "xmlrpc.php") {
                return (pass);
        }

        # pass wp-admin cookies
        if (req.http.cookie) {
            if (req.http.cookie ~ "(wordpress_|wp-settings-)") {
                return(pass);
            } else {
              unset req.http.cookie;
            }
        }
 }



sub vcl_backend_response {
    # retry a few times if backend is down
    if (beresp.status == 503 && bereq.retries < 3 ) {
       return(retry);
   }

    if (bereq.http.Cookie ~ "(UserID|_session)") {
        # if we get a session cookie...caching is a no-go
        set beresp.http.X-Cacheable = "NO:Got Session";
        set beresp.uncacheable = true;
        return (deliver);

    } elsif (beresp.ttl <= 0s) {
        # Varnish determined the object was not cacheable
        set beresp.http.X-Cacheable = "NO:Not Cacheable";

    } elsif (beresp.http.set-cookie) {
        # You don't wish to cache content for logged in users
        set beresp.http.X-Cacheable = "NO:Set-Cookie";
        set beresp.uncacheable = true;
        return (deliver);

    } elsif (beresp.http.Cache-Control ~ "private") {
        # You are respecting the Cache-Control=private header from the backend
        set beresp.http.X-Cacheable = "NO:Cache-Control=private";
        set beresp.uncacheable = true;
        return (deliver);

    } else {
        # Varnish determined the object was cacheable
        set beresp.http.X-Cacheable = "YES";

        # Remove Expires from backend, it's not long enough
        unset beresp.http.expires;

        # Set the clients TTL on this object
        set beresp.http.cache-control = "max-age=900";

        # Set how long Varnish will keep it
        set beresp.ttl = 1w;

        # marker for vcl_deliver to reset Age:
        set beresp.http.magicmarker = "1";
    }

        # unset cookies from backendresponse
        if (!(bereq.url ~ "(wp-login|wp-admin)"))  {
                set beresp.http.X-UnsetCookies = "TRUE";
                unset beresp.http.set-cookie;
                set beresp.ttl = 1h;
        }

        # long ttl for assets
        if (bereq.url ~ "\.(gif|jpg|jpeg|swf|ttf|css|js|flv|mp3|mp4|pdf|ico|png)(\?.*|)$") {
            set beresp.ttl = 365d;

}
 set beresp.grace = 1w;

}

sub vcl_hash {
   if ( req.http.X-Forwarded-Proto ) {
    hash_data( req.http.X-Forwarded-Proto );
}
}

sub vcl_backend_error {
      # display custom error page if backend down
      if (beresp.status == 503 && bereq.retries == 3) {
          synthetic(std.fileread("/etc/varnish/error503.html"));
          return(deliver);
       }
 }

sub vcl_synth {
    # redirect for http
    if (resp.status == 750) {
        set resp.status = 301;
        set resp.http.Location = req.http.x-redir;
        return(deliver);
    }
# display custom error page if backend down
    if (resp.status == 503) {
        synthetic(std.fileread("/etc/varnish/error503.html"));
        return(deliver);
     }
}


sub vcl_deliver {
    # oh noes backend is down
    if (resp.status == 503) {
        return(restart);
    }
    if (resp.http.magicmarker) {
       # Remove the magic marker
        unset resp.http.magicmarker;

       # By definition we have a fresh object
       set resp.http.age = "0";
     }
   if (obj.hits > 0) {
     set resp.http.X-Cache = "HIT";
   } else {
     set resp.http.X-Cache = "MISS";
   }
   set resp.http.Access-Control-Allow-Origin = "*";
}
sub vcl_hit {
  if (req.method == "PURGE") {
    return(synth(200,"OK"));
  }
}

sub vcl_miss {
  if (req.method == "PURGE") {
    return(synth(404,"Not cached"));
  }
}